JP2014105624A - Variable capacity type pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable capacity type pump capable of maintaining requested emission pressure as long as possible even when the number of rotation of an engine is increased in response to a request for maintaining the emission pressure to desired emission pressure.SOLUTION: At an initial position at which a spool 43 is energized by a valve spring 44 and moved to the maximum toward one axial end of a valve body 41, circulation between an introduction port 50 and a first control port 51 is limited, and the first control port 51 and a first drainage port 53 are communicated with each other. Also, when pump emission pressure is increased under a first condition that circulation between a second control part 52 and the first drainage port 53 is limited, the introduction port 50 and the first control port 51 are communicated with each other, and the circulation between the first control port 51 and the first drainage port 53 is limited. An eccentric amount of a cam ring 15 is controlled by a pilot valve 40 under a second condition that the second control port 52 and the first drainage port 53 are communicated with each other.

Description

  The present invention relates to a variable displacement pump that is applied to a hydraulic source that supplies hydraulic oil to each sliding portion of an internal combustion engine for an automobile, for example.

  As a conventional variable displacement pump applied to an internal combustion engine for automobiles, for example, the one described in Patent Document 1 below is known.

  Briefly, this variable displacement pump moves in a direction (hereinafter referred to as “eccentric direction”) in which the amount of eccentricity (referred to as the amount of eccentricity of the cam ring with respect to the rotor rotation center) increases as a whole with respect to the cam ring. A pair of springs arranged so as to be capable of applying a force and a direction in which the amount of eccentricity is reduced with respect to the cam ring as a whole by introducing the same discharge pressure into the inside (hereinafter referred to as a “concentric direction”). A pair of control oil chambers configured to be capable of imparting a moving force, the springs being arranged so as to exert urging forces in opposite directions, and concentrically as the amount of eccentricity decreases The load is increased discontinuously and stepwise. As a result, the first predetermined hydraulic pressure is maintained in the first rotational speed range and the second predetermined hydraulic pressure is maintained in the second rotational speed range. By approaching the required hydraulic pressure characteristics, it is possible to reduce wasteful energy consumption.

JP 2011-111926 A

  However, in the conventional variable displacement pump, as described above, the spring is used to restrict the operation of the cam ring, so that the cam ring becomes difficult to move as the discharge pressure increases. For this reason, even if it is attempted to maintain the discharge pressure at the first or second predetermined oil pressure, the discharge pressure greatly increases as the engine speed increases, and as a result, there is a problem of deviation from the required oil pressure characteristics. there were.

  Therefore, the present invention has been devised in view of the technical problem of the conventional variable displacement pump, and the engine speed (pump speed) increases in response to a request to maintain a desired discharge pressure. However, an object of the present invention is to provide a variable displacement pump that can maintain the required discharge pressure as much as possible.

  In particular, the present invention communicates with an introduction port for introducing hydraulic oil discharged by opening to one end side in the axial direction, a first control port communicating with the first control oil chamber, and a second control oil chamber. A valve body having a second control port and a drain port communicating with the low pressure portion, and is slidably accommodated at one axial end of the valve body, and the communication state of each port is determined according to the axial position thereof. A control mechanism having a spool to be switched and a control spring that is housed and disposed on the other axial end side of the valve body and biases the spool toward the axial one end side with a biasing force smaller than the biasing mechanism; Is initially urged by the control spring and moved to the maximum axial end of the valve body, the flow of the introduction port is restricted, and the first control port and the drain are restricted. When the port is in communication and the flow of the second control port and the drain port is restricted to be in a first state and the discharge pressure is increased, the introduction port and the first control port are in communication with each other, and The flow of the first control port and the drain port is restricted, and the second control port and the drain port are configured to be in a second state in which they communicate with each other.

  According to the present invention, the required discharge pressure can be maintained as much as possible by suppressing an increase in the discharge pressure even when the rotational speed is increased in response to the request to maintain the desired discharge pressure.

It is the schematic showing the structure and hydraulic circuit of the variable displacement pump which concerns on 1st Embodiment of this invention. It is a longitudinal cross-sectional view of the pump shown in FIG. It is the figure which looked at the pump body simple substance shown in FIG. 1 from the mating surface side with a cover member. It is a graph showing the relationship between the spring load of both springs shown in FIG. 1, and a cam ring rocking | fluctuation angle. It is a graph showing the hydraulic characteristic of the variable displacement pump which concerns on the same embodiment. It is a figure equivalent to FIG. 1 showing the state of the pump in the area b shown in FIG. 5 among the pumps according to the embodiment. It is a figure equivalent to FIG. 1 showing the state of the pump in the section c shown in FIG. 5 among the pumps according to the embodiment. It is a figure equivalent to FIG. 1 showing the state of the pump in the area d shown in FIG. 5 among the pumps according to the embodiment. It is the schematic showing the structure and hydraulic circuit of the variable displacement pump which concerns on 2nd Embodiment of this invention. It is a figure equivalent to FIG. 1 showing the state of the pump in the area b shown in FIG. 5 among the pumps according to the embodiment. It is a figure equivalent to FIG. 1 showing the state of the pump in the section c shown in FIG. 5 among the pumps according to the embodiment. It is a figure equivalent to FIG. 1 showing the state of the pump in the area d shown in FIG. 5 among the pumps according to the embodiment. It is a figure which shows the aspect of the dimension relationship of the 1st land part of a pilot valve, and a 1st control port, Comprising: (a) is the axial direction width | variety of a 1st land part, and the opening width | variety of a 1st control port is substantially the same ( b) is larger in the axial width of the first land portion than the opening width of the first control port, and (c) is larger in the opening width of the first control port than the axial width of the first land portion. , Each shows a set state. The other form of the spool (1st land part) of a pilot valve is shown, (a) is the axial direction width | variety of a 1st land part, and the opening width of a 1st control port is substantially the same, (b) is a 1st control port. The axial width of the first land portion is larger than the opening width of the first land portion, and (c) shows that the opening width of the first control port is larger than the axial width of the first land portion. Show.

  Embodiments of a variable displacement pump according to the present invention will be described below in detail with reference to the drawings. In each of the following embodiments, the variable displacement pump is applied as an oil pump that supplies engine lubricating oil to a valve timing control device that is used to control the opening / closing timing of a sliding portion of an automotive internal combustion engine or an engine valve. An example is shown.

  FIGS. 1-8 has shown 1st Embodiment of the oil pump based on this invention, This oil pump 10 is provided in each front end part of the cylinder block and balancer apparatus of an internal combustion engine outside a figure, As shown in FIG. 3, the pump body 11 has a substantially U-shaped longitudinal section with an opening formed at one end side and a pump housing chamber 13 provided therein, and a cover member 12 that closes the one end opening of the pump body 11. A pump housing, a drive shaft 14 rotatably supported by the pump housing and penetrating through a substantially central portion of the pump housing chamber 13 and rotated by a crankshaft or a balancer shaft (not shown); and the pump housing chamber 13 is a movable member accommodated in a movable (swingable) manner in the first and second control oil chambers 31 and 32 and first and second springs 33 and 34, which will be described later. The cam ring 15 constituting a variable mechanism for changing the volume change amount of the pump chamber PR, which will be described later, is housed on the inner peripheral side of the cam ring 15, and is driven to rotate counterclockwise in FIG. A pump structure that performs a pump action by increasing or decreasing the volume of a pump chamber PR that is a plurality of hydraulic oil chambers formed between the cam ring 15 and the pump housing (cover member 12); And a pilot valve 40 which is a control mechanism used for swing control of the cam ring 15 by controlling introduction or discharge of discharge pressure to the control oil chambers 31 and 32 described later.

  Here, the pump structure is rotatably accommodated on the inner peripheral side of the cam ring 15, and a rotor 16 whose central portion is coupled to the outer periphery of the drive shaft 14, and a radial notch is formed in the outer peripheral portion of the rotor 16. A plurality of slits 16 a, and a pair of ring members 18, 18 that are formed to be smaller in diameter than the rotor 16 and are disposed on both sides of the rotor 16. It is composed of

  The pump body 11 is integrally formed of an aluminum alloy material, and is driven at a substantially central position of an end wall 11a (corresponding to one side wall according to the present invention) constituting one end wall of the pump housing chamber 13. A bearing hole 11b that rotatably supports one end of the shaft 14 is formed therethrough. Further, a support groove 11c having a substantially semicircular cross section for supporting the cam ring 15 in a swingable manner via a rod-like pivot pin 19 is formed at a predetermined position on the inner peripheral wall of the pump housing chamber 13. Further, the inner peripheral wall of the pump housing chamber 13 is located on the upper half side in FIG. 1 with respect to a straight line (hereinafter referred to as “cam ring reference line”) M connecting the center of the bearing hole 11b and the center of the support groove 11b. A seal slidable contact surface 11d is formed on which the seal member 20 disposed on the outer periphery of the cam ring 15 is slidably contacted. The seal slidable contact surface 11d is formed in a circular arc shape having a predetermined radius R1 from the center of the support groove 11c, and the circumferential length of the seal member 20 is always slidable within a range in which the cam ring 15 is eccentrically swung. Is set. Similarly, on the lower half side in FIG. 1 with respect to the cam ring reference line M, a seal slidable contact surface 11e with which the seal member 20 disposed on the outer peripheral portion of the cam ring 15 is slidably contacted is formed. The seal slidable contact surface 11e is formed in a circular arc shape having a predetermined radius R2 from the center of the support groove 11c, and has a circumferential length that allows the seal member 20 to always slidably contact within a range in which the cam ring 15 is eccentrically swung. Is set.

  In addition, on the inner surface of the end wall 11a of the pump body 11, particularly as shown in FIG. 1 and FIG. 3, in the outer peripheral area of the bearing hole 11b, each pump chamber PR is provided along with the pump action by the pump structure. A suction port 21a, which is a substantially arc-shaped suction portion so as to open to a region in which the volume increases (hereinafter referred to as “suction region”), and a region in which the volume of each pump chamber PR decreases (hereinafter referred to as “discharge region”). The discharge port 22a, which is a substantially arc-shaped discharge portion, is cut out so as to substantially face each other across the bearing hole 11b.

  The suction port 21a is integrally provided with an introduction portion 23 formed so as to bulge toward the first spring accommodating chamber 28 described later at a substantially intermediate position in the circumferential direction. In the vicinity of the boundary portion of the port 21a, a suction port 21b penetrating through the end wall 11a of the pump body 11 and opening to the outside is formed. With this configuration, the lubricating oil stored in the oil pan (not shown) of the internal combustion engine is related to the suction region via the suction port 21b and the suction port 21a based on the negative pressure generated by the pump action of the pump structure. The pump chamber PR is inhaled. Here, the inlet 21 a is configured to communicate with the low pressure chamber 35 formed in the outer peripheral area of the cam ring 15 in the suction area together with the introduction portion 23, and the suction pressure is also in the low pressure chamber 35. It is designed to guide low pressure oil.

  The discharge port 22a is formed with a discharge port 22b penetrating through the end wall 11a of the pump body 11 and opening to the outside at the start end. With this configuration, the oil pressurized and discharged to the discharge port 22a by the pumping action of the pump structure body is changed in the engine through the main oil gallery OG provided in the cylinder block from the discharge port 22b. It is supplied to a sliding part, a valve timing control device, etc. (all not shown).

  The discharge port 22a is formed with a communication groove 25a that communicates the discharge port 22a and the bearing hole 11b. Oil is supplied to the bearing hole 11b through the communication groove 25a and the rotor 16 and By supplying oil also to the side part of each vane 17, good lubrication of each sliding part is secured. The communication groove 25a is formed so as not to coincide with the direction in which the vanes 17 protrude and retract, and is prevented from dropping into the communication groove 25a when the vanes 17 appear and disappear.

  The cover member 12 constitutes the other side wall according to the present invention, and has a substantially plate shape as shown in FIG. 2, and is attached to the opening end surface of the pump body 11 by a plurality of bolts B1. Thus, a bearing hole 12a that rotatably supports the other end of the drive shaft 14 is formed at a position facing the bearing hole 11b of the pump body 11. Further, similarly to the pump body 11, the suction port 21c, the discharge port 22c, and the communication groove 25b are also provided on the inner surface of the cover member 12 with respect to the suction port 21a, the discharge port 22a, and the communication groove 25a of the pump body 11. Are opposed to each other.

  The drive shaft 14 is connected to a crankshaft (not shown) or the like at one end in the axial direction that passes through the end wall 11a of the pump body 11 and faces the outside, and is subjected to the rotational force transmitted from the crankshaft or the like. Based on this, the rotor 16 is rotated clockwise in FIG. Here, as shown in FIG. 1, a straight line (hereinafter referred to as “cam ring eccentric direction line”) N passing through the center of the drive shaft 14 and perpendicular to the cam ring reference line M is defined between the suction region and the discharge region. It is a boundary.

  The rotor 16 has the plurality of slits 16a formed radially from the center side to the radially outer side, and has a substantially circular cross section for introducing discharged oil to the inner base end of each slit 16a. A back pressure chamber 16b having a shape is provided, and the vanes 17 are pushed outward by the centrifugal force accompanying the rotation of the rotor 16 and the pressure in the back pressure chamber 16b.

  Each vane 17 has its distal end surface in sliding contact with the inner peripheral surface of the cam ring 15 and each proximal end surface in sliding contact with the outer peripheral surface of each of the ring members 18 and 18 when the rotor 16 rotates. Yes. That is, each vane 17 is configured to be pushed up radially outward of the rotor 16 by the ring members 18 and 18, the engine speed is low, the centrifugal force and the pressure in the back pressure chamber 16b. Is small, each tip is in sliding contact with the inner peripheral surface of the cam ring 15 so that the pump chambers PR are liquid-tightly separated.

  The cam ring 15 is integrally formed of a so-called sintered metal in a substantially cylindrical shape, and in a predetermined position on the outer periphery thereof, a pivot portion having a substantially circular arc groove shape that forms an eccentric rocking fulcrum by fitting with a pivot pin 19. 15a is notched along the axial direction, and at a position on the opposite side of the center of the cam ring 15 with respect to the pivot portion 15a, a first spring constant set to a predetermined spring constant is provided. An arm portion 15b that projects from the first spring 33 and the second spring 34 set to a smaller spring constant than the first spring 33 projects in the radial direction. The arm portion 15b is provided with a substantially arc-shaped pressing protrusion 15c on one side of the moving (turning) direction thereof, and on the other side, a restricting portion 28 described later. The pressing protrusion 15d is set to be longer than the thickness width, the pressing protrusion 15c is at the distal end of the first spring 33, and the pressing protrusion 15d is at the distal end of the second spring 34, respectively. By always abutting, the arm portion 15b and the springs 33 and 34 are linked.

  Further, as shown in FIGS. 1 and 3, the first and second springs 33 and 34 are accommodated and held in the pump body 11 at positions facing the support groove 11b. The second spring accommodating chambers 26 and 27 are provided adjacent to the pump accommodating chamber 13 along the cam ring eccentric direction line N in FIG. The first spring 33 is elastically mounted with a predetermined set load W1 between the first spring 33 and the arm portion 15b (pressing protrusion 15c), while the end wall and the arm portion 15b ( A second spring 34 having a smaller wire diameter than the first spring 33 is elastically mounted with a predetermined set load W2 between the pressing protrusion 15d). Between the first and second spring accommodating chambers 26 and 27, a restricting portion 28 having a step shape is provided, and the other side portion of the arm portion 15b is connected to one side portion of the restricting portion 28. While the contact portion restricts the clockwise rotation range of the arm portion 15b, the maximum extension amount of the second spring 34 is achieved when the tip of the second spring 34 contacts the other side portion of the restriction portion 28. Are now regulated.

  Thus, with respect to the cam ring 15, the arm portion 15b is moved with the resultant force W0 of the set loads W1 and W2 of the springs 33 and 34, that is, the biasing force of the first spring 33 that exerts a relatively large spring load. As shown in FIG. 1, the pressing protrusion 15d of the arm portion 15b is in the second state by being constantly biased in the direction in which the amount of eccentricity increases (clockwise in FIG. 1). The second spring 34 is compressed by entering the spring accommodating chamber 27, and the other side portion of the arm portion 15b is pressed against one side portion of the restricting portion 28. As a result, the amount of eccentricity is maximized. It is regulated at the position.

  Further, on the outer peripheral portion of the cam ring 15, the seal sliding contact surfaces 11d and 11e formed to face the first and second seal sliding contact surfaces 11d and 11e formed by the inner peripheral wall of the pump body 11, respectively. A pair of first and second seal components 15e and 15f having first and second seal surfaces 15g and 15h that are concentric with each other are projected, and each seal surface 15g of each seal component 15e and 15f is projected. 15h, a seal holding groove 15i is formed along the axial direction. The seal holding groove 15i is in sliding contact with the seal sliding contact surfaces 11d and 11e when the cam ring 15 is eccentrically swung. The first and second seal members 20a and 20b are accommodated and held, respectively.

  Here, the first and second seal surfaces 15g and 15h are configured with predetermined radii r1 and r2 slightly smaller than the radii R1 and R2 constituting the seal sliding contact surfaces 11d and 11e, respectively. A predetermined minute clearance is formed between the seal sliding contact surfaces 11d and 11e and the seal surfaces 15g and 15h. On the other hand, each of the first and second seal members 20a and 20b is formed in an elongated shape linearly along the axial direction of the cam ring 15 with, for example, a fluorine-based resin material having low friction characteristics, and the bottom of each seal holding groove 15i. Are pressed against the seal sliding contact surfaces 11d and 11e with the elastic force of the rubber elastic members respectively disposed between the seal sliding contact surfaces 11d and 11e and the seal surfaces 15g and 15h. Will be liquid-tightly separated.

  Further, a pair of first and second control oil chambers 31 and 32 are separated from each other by the pivot pin 19 and the first and second seal members 20 a and 20 b in the outer peripheral area of the cam ring 15. The control oil chambers 31 and 32 are configured such that the hydraulic pressure in the engine corresponding to the pump discharge pressure is guided through a control pressure introduction passage 60 branched from the main oil gallery OG. Specifically, pump discharge pressure is supplied to the first control oil chamber 31 through the pilot valve 40 through the first introduction passage 61 which is one branch passage branched further from the control pressure introduction passage 60. On the other hand, the second control oil chamber 32 is supplied with the pump discharge pressure having passed through a predetermined throttle 63 through the second introduction passage 62 which is the other branch passage. Note that F1 and F2 in FIG. 1 both indicate an oil filter composed of filter paper or the like.

  These hydraulic pressures act on the pressure receiving surfaces 15j and 15k constituted by the outer peripheral surfaces of the cam ring 15 facing the first and second control oil chambers 31 and 32, respectively, so that a swinging force ( (Movement amount) is given. Here, the pressure receiving surfaces 15j and 15k are set so that the first pressure receiving surface 15j is larger than the second pressure receiving surface 15k, and when the same oil pressure acts on both, The cam ring 15 can be urged in the direction of decreasing the eccentricity (counterclockwise in FIG. 1). In other words, the control oil chambers 31 and 32 urge the cam ring 15 in the concentric direction via the pressure receiving surfaces 15j and 15k with the internal pressure acting in the opposite direction. It is used for movement control in the concentric direction.

  From such a configuration, in the oil pump 10, the biasing force in the eccentric direction based on the spring load of the first spring 33, the biasing force in the concentric direction based on the spring load of the second spring 34 and the internal pressure of the control oil chamber 30, Are balanced with a predetermined force relationship, and the resultant force W0 (= the set load of both springs 33, 34, which is the difference between the set load W1 of the first spring 33 and the set load W2 of the second spring 34). When the urging force based on the internal pressures of the two control oil chambers 31 and 32 is small with respect to W1-W2), the cam ring 15 is in the maximum eccentric state as shown in FIG. When the urging force based on the internal pressure of the springs 31 and 32 exceeds the resultant force W0 of the set load of the springs 33 and 34, the cam ring 15 is concentric in accordance with the discharge pressure. So that the moving.

  If the relationship between the spring load W of the springs 33 and 34 and the swing angle (movement amount) X of the cam ring 15 is specifically described, as shown in FIG. 4, the cam ring 15 is in the maximum eccentric state. When the biasing force based on the internal pressures of the control oil chambers 31 and 32 reaches the resultant force W0 of the set loads W1 and W2 of the springs 33 and 34 corresponding to the biasing force based on the first switching oil pressure Pf described later at the position X1. The first spring 33 contracts, while the second spring 35 begins to expand, and the cam ring 15 moves in the concentric direction. Eventually, as the discharge pressure increases, the urging force based on the internal pressure of the control oil chambers 31 and 32 increases, and when the second spring 34 comes into contact with the restricting portion 30, the assisting action by the second spring 35 is lost. The cam ring 15 stops moving concentrically (position X2 in the figure). When the discharge pressure further increases and the urging force based on the internal pressures of the control oil chambers 31 and 32 reaches the spring load Wx of the first spring 33 corresponding to the urging force based on the second switching oil pressure Ps described later, The first spring 33 starts to contract further, and the cam ring 15 further moves in the concentric direction (position X3 in the figure).

  As shown in FIG. 1 in particular, the pilot valve 40 is provided integrally with the cover member 12, for example (regardless of specific arrangement), and opens at one end side with a stepped diameter and the other end side with a stepped diameter. A formed tubular valve body 41, a plug 42 for closing the other end side opening of the valve body 41, and an axially slidable housing on the inner peripheral side of the valve body 41, the valve A spool 43 for controlling supply / discharge of hydraulic pressure to / from the second control oil chamber 32 by using a first and second land portions 43a and 43b which are a pair of large-diameter portions that are in sliding contact with the inner peripheral surface of the body 41; A valve spring 44 which is elastically mounted with a predetermined set load Wk between the plug 42 and the spool 43 on the inner periphery on the other end side of the valve 41 and constantly biases the spool 43 toward the one end side of the valve body 41. To have.

  The valve body 41 is provided with a valve housing portion 41a having a cylindrical body having an inner diameter substantially the same as the outer diameter of the spool 43 (the outer diameter of each of the land portions 43a and 43b) in a range excluding both axial end portions. Thus, the spool 43 is accommodated in the valve accommodating portion 41a. An opening port 50 connected to the second introduction passage 72 is opened at one end portion of the small diameter shape, and a female thread portion provided on an inner peripheral portion thereof is formed at the other end portion of the large diameter shape. The plug 42 is screwed through.

  Further, on the peripheral wall of the valve accommodating portion 41a, the first control port 51 connected to the introduction port 50 or the first drain port 53 described later, the communication between the second control oil chamber 32 and the first drain port 53 described later. Also, the second control port 52 used for switching the restriction state, one end side is connected to a low pressure portion such as a suction side or an oil pan (not shown), and the other end side is connected to the control ports 51 and 52, and the control oil chambers 31 are connected. , 32 is connected to a first drain port 53 for discharging oil in the back pressure chamber 57, one end side is connected to the low pressure portion, and the other end side is connected to a back pressure chamber 57 described later, and a second drain port is used to discharge oil in the back pressure chamber 57. A drain port 54 is formed in the opening.

  The spool 43 is provided with the large-diameter first and second land portions 43a and 43b at both axial ends thereof, and a shaft portion 43c which is a small-diameter portion between the land portions 43a and 43b. Is provided. When the spool 43 is accommodated in the valve accommodating portion 41a, the spool accommodating portion 41a is provided between the first land portion 43a and one end of the valve body 41 on the outer side in the axial direction. The pressure chamber 55 through which the discharge pressure is guided from the introduction port 51 through the one introduction passage 61 and the land portions 43 a and 43 b are provided between the first control port 52 or the second control port 52 depending on the axial position of the spool 43. The relay chamber 56 is provided between the relay chamber 56 for relaying the first drain port 53 and the plug 42 on the axially outer side of the second land portion 43b, and is connected to the relay chamber 56 through the outer peripheral side (small gap) of the second land portion 43b. The back pressure chamber 57 for discharging the more leaked oil is separated from each other.

  With such a configuration, the pilot valve 40 is configured so that the discharge pressure guided from the introduction port 51 to the pressure chamber 56 is not more than a predetermined pressure (first switching oil pressure Pf described later) as shown in FIG. Due to the urging force of the valve spring 44 based on the load Wk, the first land portion 43a of the spool 43 comes into a first state where it abuts against one end wall of the valve housing portion 41a. That is, in the first state, the communication of the introduction port 50 is blocked by the first land portion 43a, and the first control port 51 and the first drain port 53 are connected via the relay chamber 56, As a result of the communication of the second control port 52 being blocked by the second land portion 43b (hereinafter, the predetermined connection between the control ports 51 and 52 including the state where the spool 43 is in contact with one end wall of the valve accommodating portion 41a) The axial position of the spool 43 that causes the state is referred to as “first region”), and the oil in the first control oil chamber 31 is discharged and discharged only to the second control oil chamber 32 through the second introduction passage 62. Pressure will be supplied. Note that “blocking” in the pilot valve 40 does not mean that any flow is blocked, but a small amount of flow through a minute gap formed on the outer peripheral side of each land portion 43a, 43b occurs. It is meant to include those that are formally restricted in distribution (the same shall apply hereinafter).

  When the discharge pressure guided to the pressure chamber 56 exceeds the predetermined pressure, the spool 43 moves from the first state to the plug 42 side against the urging force of the valve spring 44. (See FIG. 8). More specifically, in a state where the discharge pressure is higher than the first switching hydraulic pressure Pf that is the predetermined pressure and is equal to or lower than a second switching hydraulic pressure Ps described later, the spool 43 is positioned in the second region that is an intermediate region (FIG. 6). 7), the first land portion 43a connects the introduction port 50 and the first control port 51 via the pressure chamber 55, and the communication between the first control port 51 and the first drain port 53 is blocked. On the other hand, as a result of maintaining the cutoff state of the second control port 52 by the second land portion 43b, the discharge pressure is supplied from the first introduction passage 61 to the first control oil chamber 31 via the pilot valve 40. The discharge pressure is also supplied to the second control oil chamber 32 through the second introduction passage 62. When the discharge pressure exceeds the second switching hydraulic pressure Ps, the spool 43 is in the second state located in the third region close to the plug 42 (see FIG. 8), and is caused by the first land portion 43a. As a result, the communication state between the introduction port 50 and the first control port 51 is maintained, while the second control port 52 and the first drain port 53 are connected via the relay chamber 56 by the second land portion 43b. The oil in the second control oil chamber 32 is discharged, and the discharge pressure is supplied only to the first control oil chamber 31.

  Below, the characteristic effect | action of the oil pump 10 which concerns on this embodiment is demonstrated based on FIG. 1, FIG. 5-FIG.

  First, before entering the description of the operation of the oil pump 10, the required oil pressure of the internal combustion engine that is a reference for the discharge pressure control of the oil pump 10 will be described with reference to FIG. P2 in the figure is the first engine required oil pressure corresponding to the required oil pressure of the device when the valve timing control device used for improvement is adopted, and P2 in the figure is the request of the device when the oil jet used for cooling the piston is used The second engine required oil pressure corresponding to the oil pressure, P3 in the figure indicates the third engine required oil pressure required for lubrication of the bearing portion of the crankshaft at the time of high engine rotation, and these points P1 to P3 are indicated by alternate long and short dashed lines. What is connected represents an ideal required oil pressure (discharge pressure) P corresponding to the engine speed R of the internal combustion engine. In the figure, the solid line represents the hydraulic characteristic of the oil pump 10 according to the present invention, and the broken line represents the hydraulic characteristic of the conventional pump.

  Further, Pf in the figure is the first switching hydraulic pressure at which the spool 43 starts to move from the first region to the second region against the urging force Wk of the valve spring 44, and Ps is the valve 43 that the spool 43 has. The second switching oil pressures that start further movement from the second region to the third region against the urging force W are respectively shown. Further, in the oil pump 10, the cam oil pressure of the cam ring 15 when the urging forces W 1 and W 2 by the first and second springs 33 and 34 as shown in FIG. The first hydraulic pressure) is smaller than the first switching hydraulic pressure Pf, and the hydraulic pressure of the cam ring 15 (second hydraulic pressure) when only the urging force W1 by the first spring 33 as shown in FIG. Is set to be larger than the second switching oil pressure Ps, the spring loads of the springs 33 and 34 and the areas of the pressure receiving surfaces 15j and 15k of the control oil chambers 31 and 32 are set.

  From such a setting, in the case of the oil pump 10, the discharge pressure (in-engine hydraulic pressure) P is greater than the first switching hydraulic pressure Pf in the section a in FIG. Therefore, as shown in FIG. 1, the pilot valve 40 is in the first state, that is, the spool 43 is positioned in the first region, the communication of the introduction port 50 is blocked by the first land portion 43a, and The first control port 51 and the first drain port 53 are connected via the relay chamber 56, while the second land port 43b blocks the communication of the second control port 52. As a result, the oil in the first control oil chamber 31 is discharged to the low pressure portion, and the discharge pressure P is supplied only to the second control oil chamber 32 via the second introduction passage 62, so that the second control Due to the urging force based on the internal pressure of the oil chamber 32 and the resultant force W0 of the two springs 33, 34, that is, the urging force based on the relatively large spring load of the first spring 33, the cam ring 15 and the arm portion 15b are regulated. 28 is held in the maximum eccentric state in contact with 28. As a result, the discharge amount of the pump is maximized, and the discharge pressure P also increases in proportion to the increase in the engine speed R.

  Thereafter, when the engine speed R increases and the discharge pressure P reaches the first switching oil pressure Pf (see FIG. 5), as shown in FIG. 6, in the pilot valve 40, the spool 43 is biased by the valve spring Wk. Against this, it moves to the plug 42 side and switches from the first region to the second region. Thereby, the introduction port 50 and the first control port 51 are connected via the pressure chamber 55 by the first land portion 43a, and the communication between the first control port 51 and the first drain port 53 is blocked, As a result of maintaining the shutoff state of the second control port 52 by the second land portion 43b, the discharge pressure is supplied from the first introduction passage 61 to the first control oil chamber 31, and the second control oil continues. The discharge pressure is also supplied to the chamber 32 from the second introduction passage 62. As a result, the resultant force of the urging force based on the internal pressure of the first control oil chamber 31 and the urging force W2 of the second spring 34 is the urging force W1 of the first spring 33 and the urging force based on the internal pressure of the second control oil chamber 32. Overcoming the resultant force, the cam ring 15 starts moving in the concentric direction.

  Then, the discharge pressure P decreases due to a decrease in the amount of eccentricity accompanying the concentric movement of the cam ring 15, and the urging force based on the discharge pressure P falls below the urging force Wk by the valve spring 44. With the urging force Wk of 44, the spool 43 is pushed back from the second area to the first area. That is, the connection of the first control port 53 is switched by the first land portion 43 a of the spool 43 pushed back, and the first control port 53 is connected to the first drain port 53 via the relay chamber 55 again. . As a result, the oil in the first control oil chamber 31 is discharged and the internal pressure of the first control oil chamber 31 is reduced. The biasing force based on the internal pressure of the first control oil chamber 31 and the second spring 34 are Since the resultant force with the urging force W2 is less than the first urging force acting in the direction of increasing eccentricity, the cam ring 15 is again in the maximum eccentric state as shown in FIG. When the discharge pressure P rises again based on this maximum eccentric state and the urging force based on the discharge pressure P overcomes the urging force Wk of the valve spring 44, the urging force Wk of the valve spring 44 is resisted. As a result, the spool 43 moves again to the plug 42 side and switches from the first area to the second area, and as a result, the cam ring 15 moves again in the concentric direction as described above.

  As described above, in the oil pump 10, the connection of the first control port 51 is continuously and alternately switched between the communication state with the first drain port 53 or the communication state with the introduction port 50 by the spool 43 in the pilot valve 40. Thus, the discharge pressure P is adjusted to be maintained at the first switching oil pressure Pf. Such pressure regulation is performed by switching the first control port 51 described above in the pilot valve 40, so that it is not affected by the spring constants of the first and second springs 33 and 34. In addition, since the pressure adjustment is performed in the extremely narrow stroke range of the spool 43 related to the switching of the first control port 51 described above, there is no possibility of being influenced by the spring constant of the valve spring 44. As a result, the discharge pressure P of the oil pump 10 does not increase proportionally with the increase in the engine speed R as in the conventional pump indicated by the broken line in FIG. It is possible to make it as close as possible to the ideal required oil pressure (dashed line in FIG. 5) (section b in FIG. 5). Thereby, in the oil pump 10 according to the present embodiment, compared with the conventional oil pump in which the discharge pressure P is inevitably increased by the spring constant of the first spring 33 as the engine speed R increases. It is possible to reduce power loss (range S1 indicated by hatching in FIG. 5) caused by unnecessarily increasing the discharge pressure P. Further, since the cam ring 15 is controlled by introducing the hydraulic pressure into the control oil chambers 31 and 32 by the operation of the pilot valve 40, the discharge pressure P is controlled without being affected by the internal pressure fluctuation due to oil temperature change or aeration. Is possible.

  Eventually, when the pilot valve 40 is in the second region, the discharge pressure P increases as the engine speed R increases, and the first control port 51 and the pressure chamber 55 are sufficiently communicated. 1 When the internal pressure of the control oil chamber 31 rises and the cam ring 15 moves in the concentric direction, the tip of the second spring 34 comes into contact with the restricting portion 28 (see FIG. 7). That is, the assisting action by the second spring 34 is lost, and the movement of the cam ring 15 in the concentric direction is stopped. As a result, the discharge pressure P increases again in proportion to the engine speed R as the engine speed R increases (section c in FIG. 5). In the section c, the amount of eccentricity of the cam ring 15 is smaller than that in the section a. Therefore, the increase amount of the discharge pressure P is smaller than that in the section a.

  Then, when the discharge pressure P further increases due to the increase in the engine speed R according to such characteristics, when the discharge pressure P reaches the second switching hydraulic pressure Ps, the pilot valve 40 at the pilot valve 40 as shown in FIG. Then, the spool 43 further moves toward the plug 42 and switches from the second area to the third area. As a result, the first control port 51 is maintained in communication with the introduction port 51, while the second control port 52 is connected to the first drain port 53 via the relay chamber 55. The discharge pressure P is introduced into the first control oil chamber 31, and the oil is discharged from the second control oil chamber 32. Here, since the second control oil chamber 32 is configured to communicate with the control pressure introduction passage 60 via the restrictor 63, oil is discharged through communication between the second control port 52 and the first drain port 53. When this occurs, a pressure loss occurs in the throttle 63, and the hydraulic pressure introduced into the second control oil chamber 32 decreases. As a result, the biasing force based on the internal pressure of the first control oil chamber 31 exceeds the resultant force of the biasing force W1 of the first spring 33 and the biasing force based on the internal pressure of the second control oil chamber 32, and the cam ring 15 Further movement will be started in the concentric direction.

  Then, the discharge pressure P decreases due to a decrease in the amount of eccentricity accompanying the concentric movement of the cam ring 15, and the urging force based on the discharge pressure P falls below the urging force Wk by the valve spring 44. With the urging force Wk of 44, the spool 43 is pushed back from the third area to the second area. That is, the connection of the second control port 52 is switched by the pushed second land portion 43b of the spool 43, and the second control port 52 is shut off again. As a result, the introduction of the discharge pressure P to the second control oil chamber 32 causes the internal pressure of the second control oil chamber 32 to rise again. As a result, the biasing force based on the internal pressure of the first control oil chamber 31 increases in the eccentricity increasing direction. Therefore, the cam ring 15 is again in an intermediate eccentric state as shown in FIG. Then, when the discharge pressure P rises again based on the increase in the amount of intermediate eccentricity and the urging force based on the discharge pressure P overcomes the urging force Wk of the valve spring 44, the urging force Wk of the valve spring 44 is increased. Accordingly, as a result of the spool 43 moving again toward the plug 42 and switching from the second region to the third region, the cam ring 15 moves again in the concentric direction as described above (section in FIG. 5). d).

  As described above, the oil pump 10 is configured such that the connection of the second control port 52 is continuously and alternately switched from the communication state or the cutoff state with the first drain port 53 by the spool 43 in the pilot valve 40. Is adjusted to be maintained at the second switching oil pressure Ps. Since the pressure regulation is performed by switching the second control port 52 described above in the pilot valve 40, the pressure regulation is not affected by the spring constants of the first and second springs 33, 34. Is performed within the range of the extremely narrow stroke of the spool 43 related to the switching of the second control port 52 described above, and therefore is not affected by the spring constant of the valve spring 44. As a result, as in the case of the section b, the discharge pressure P of the oil pump 10 does not increase proportionally as the engine speed R increases as in the conventional pump (broken line in FIG. 5). Therefore, the discharge pressure P is inevitably increased by the spring constant of the first spring 33 as the engine speed R is increased. As compared with the conventional oil pump, the power loss (range S2 indicated by hatching in FIG. 5) caused by unnecessarily increasing the discharge pressure P can be reduced. In addition, since the cam ring 15 is controlled by introducing hydraulic pressure to the control oil chambers 31 and 32 based on the operation of the pilot valve 40, the discharge pressure P is not affected by changes in the oil pressure, aeration, or the like. Can be controlled.

  From the above, in the oil pump 10, the engine speed range (section b and section in FIG. 5) required to be maintained at desired discharge pressures (first switching hydraulic pressure Pf and second switching hydraulic pressure Ps), respectively. In d), the discharge pressure P can be maintained at the desired discharge pressure.

  Moreover, since this pressure regulation is performed by the pilot valve 40, it is not affected by the spring constants of the first and second springs 33 and 34 as in the prior art. Further, in the pilot valve 40 as well, the pressure regulation is performed within a very narrow stroke range of the spool 43, so that it is not affected by the spring constant of the valve spring 44. In other words, the desired pressure can be avoided without causing a disadvantage that the discharge pressure P is unnecessarily increased due to the influence of the spring constant of both the springs 33 and 34 (particularly the first spring 33) including the valve spring 44. The discharge pressure can be maintained.

  In addition, in the oil pump 10, when the spool 43 is in the first region at the time of the pressure adjustment, the first control oil chamber 31 (first control port 51) is communicated with the first drain port 53, and the control oil chamber Since the discharge pressure P is introduced only into the second control oil chamber 32 in order to discharge the oil in the cam 31, the cam ring 15 is caused by the hydraulic pressure being supplied to both the control oil chambers 31 and 32. Unstable operations such as fluttering are suppressed, and the cam ring 15 can be held stably. As a result, the discharge pressure control in the section a is also stabilized.

  9 to 12 show a second embodiment of the variable displacement pump according to the present invention, in which the supply mode of hydraulic pressure (discharge pressure) to the second control oil chamber 32 according to the first embodiment is changed. Thus, the hydraulic pressure is not directly supplied to the second control oil chamber 32 through an individual oil passage such as the second introduction passage 62 as in the first embodiment, but the pilot valve 40 is the same as the first control oil chamber 31. The hydraulic pressure is supplied to the second control oil chamber 32 via

  That is, in the present embodiment, the first and second control ports 51 and 52 of the pilot valve 40 are connected to the first and second control oil chambers 31 and 32 via the first and second supply / discharge passages 65 and 66, respectively. The two supply / discharge ports 65 and 66 are connected to each other via a connection passage 67 having a restriction 68. The connection passage 67 itself can be provided inside or outside the oil pump 10, but when provided inside the pump, for example, it is provided in a groove shape on the joint surface between the pump body 11 and the cover member 12. By doing so, the enlargement of the pump can be avoided.

  Hereinafter, the characteristic operation of the oil pump 10 according to the present embodiment will be described with reference to FIGS. 5 and 9 to 12.

  Since the discharge pressure P is smaller than the first switching oil pressure Pf in the section a in FIG. 5 after the engine is started, the pilot valve 40 is in the first state, that is, the spool 43 is in the first state as shown in FIG. The first land portion 43a blocks the communication of the introduction port 50, and the first control port 51 and the first drain port 53 are connected via the relay chamber 56, and the second land portion The communication of the second control port 52 is blocked by 43b. As a result, the oil in the first control oil chamber 31 is discharged to the low pressure portion, and no hydraulic pressure is supplied to any of the first and second control oil chambers 31, 32. Only the resultant force W0 of the second springs 33 and 34, that is, the urging force based on the relatively large spring load of the first spring 33 acts. Therefore, the cam ring 15 is held in the maximum eccentric state, the pump discharge amount becomes maximum, and the discharge pressure P also increases in proportion to the increase in the engine speed R.

  Thereafter, when the engine speed R increases and the discharge pressure P reaches the first switching oil pressure Pf, the spool 43 is plugged against the urging force Wk of the valve spring in the pilot valve 40 as shown in FIG. It moves to 42 side and switches from the 1st field to the 2nd field. Thereby, the introduction port 50 and the first control port 51 are connected via the pressure chamber 55 by the first land portion 43a, and the communication between the first control port 51 and the first drain port 53 is blocked, As a result of maintaining the cutoff state of the second control port 52 by the second land portion 43b, the hydraulic pressure introduced from the introduction port 50 is supplied to the first control oil chamber 31 through the first supply / discharge passage 65 and connected. The second control oil chamber 32 is also supplied through the passage 67 and the second supply / discharge passage 66. At this time, as described above, the second control port 52 is shut off, and no oil is discharged from the second control oil chamber 32, so that no pressure loss occurs in the throttle 68, and the second control oil chamber 32. Is the same internal pressure of the first control oil chamber 31. As a result, the resultant force of the urging force based on the internal pressure of the first control oil chamber 31 and the urging force W2 of the second spring 34 is the urging force W1 of the first spring 33 and the urging force based on the internal pressure of the second control oil chamber 32. Overcoming the resultant force, the cam ring 15 starts moving in the concentric direction.

  Then, the spool 43 moves back and forth between the first region and the second region, so that the connection of the first control port 51 is switched continuously and alternately between the communication state with the first drain port 53 or the communication state with the introduction port 50. Based on the same action as in the first embodiment, the discharge pressure P is adjusted to be maintained at the first switching oil pressure Pf. As a result, the discharge pressure P does not increase proportionally with the increase in the engine speed R as in the conventional pump indicated by the broken line in FIG. Can be made as close as possible to the ideal required oil pressure (a chain line in FIG. 5) (section b in FIG. 5).

  Eventually, when the pilot valve 40 is in the second region, the discharge pressure P increases as the engine speed R increases, and the first control port 51 and the pressure chamber 55 are sufficiently communicated. 11, the tip of the second spring 34 comes into contact with the restricting portion 28 as the cam ring 15 moves in the concentric direction. Thereby, the assisting action by the second spring 34 is lost, and the movement of the cam ring 15 in the concentric direction is stopped. As a result, as the engine speed R increases, the discharge pressure P increases again in an almost proportional manner to the engine speed R with an increase smaller than the section a, as in the first embodiment. (Section c in FIG. 5).

  Then, when the engine speed R increases according to such characteristics and the discharge pressure P further increases, when the discharge pressure P reaches the second switching oil pressure Ps, the pilot valve 40 has the pilot valve 40 as shown in FIG. Then, the spool 43 further moves toward the plug 42 and switches from the second area to the third area. As a result, the first control port 51 is maintained in communication with the introduction port 51, while the second control port 52 is connected to the first drain port 53 via the relay chamber 55. The discharge pressure P is introduced into the first control oil chamber 31, and the oil is discharged from the second control oil chamber 32. As a result, a pressure loss occurs in the throttle 68 and the hydraulic pressure introduced into the second control oil chamber 32 decreases, so that the urging force based on the internal pressure of the first control oil chamber 31 is applied to the first spring 33. The resultant force of the urging force W1 and the urging force based on the internal pressure of the second control oil chamber 32 is exceeded, and the cam ring 15 starts to move further in the concentric direction.

  Then, the spool 43 moves back and forth between the second region and the third region, so that the connection of the second control port 52 is continuously and alternately switched from the communication state or the cutoff state to the first drain port 53. Based on the same action as the embodiment, the discharge pressure P is adjusted to be maintained at the first switching oil pressure Ps. As a result, the discharge pressure P does not increase proportionally with the increase in the engine speed R as in the conventional pump indicated by the broken line in FIG. Can be made as close as possible to the ideal required oil pressure (dashed line in FIG. 5) (section d in FIG. 5).

  As described above, also in the present embodiment, as a result of the same operational effects as in the first embodiment, the discharge pressure P is set in the engine speed range in which it is required to maintain a desired discharge pressure. The desired discharge pressure can be maintained.

  The present invention is not limited to the configuration of each of the above-described embodiments. For example, with respect to the engine required oil pressures P1 to P3 and the first and second switching oil pressures Pf and Ps, the internal combustion of the vehicle on which the oil pump 10 is mounted. It can be freely changed according to the specifications of the engine and the valve timing control device.

  Further, in each of the above embodiments, the connection between the first control port 51 and the introduction port 50 or the first drain port 53 is switched at the same time by the first land portion 43a. The following various configurations can be adopted.

  For example, with respect to the dimension setting, as shown in FIG. 13A, the axial width L1 of the first land portion 43a and the opening width L0 of the first control port 51 are set to be substantially equal, as shown in FIG. Thus, the axial width L1 of the first land portion 43a is set to be slightly larger than the opening width L0 of the first control port 51, or the axial width L1 of the first land portion 43a is set as shown in FIG. It is possible to adopt an arbitrary dimension setting such that the opening width L0 of the first control port 51 is slightly larger than the opening width L0. In this way, by changing the axial width L1 of the first land portion 43a and the opening width L0 of the first control port 51 relative to each other, the hydraulic pressure to the first control oil chamber 31 or the like corresponding to the stroke of the spool 43 is obtained. It is possible to arbitrarily control the supply amount. Further, tapered chamfered portions 43d and 43d may be formed on both end sides of the first land portion 43a while maintaining the dimension setting (see FIG. 14).

  In each of the above-described embodiments, the variable displacement vane pump has been described as an example. Therefore, the cam ring 15 corresponds to the variable member according to the present invention, and the cam ring 15 provided in a swingable manner and both control oils disposed on the outer peripheral side thereof. The chambers 31 and 32 and the coil spring 33 constitute a variable mechanism. However, when the present invention is applied to other types of variable displacement pumps, for example, trochoid pumps, the outer rotor constituting the external gear is the aforementioned Corresponds to the movable member. The variable mechanism is configured by disposing the outer rotor so as to be eccentrically movable like the cam ring 15 and disposing the control oil chamber and the spring on the outer peripheral side thereof.

  Further, in each of the above embodiments, the mode in which the discharge amount is made variable by swinging the cam ring 15 is described as an example. However, as the means for making the discharge amount variable, the swing-related means is described above. For example, the cam ring 15 may be linearly moved in the radial direction. In other words, the mode of movement of the cam ring 15 is not limited as long as the discharge amount can be changed (the volume change amount of the pump chamber PR can be changed).

  In the following, technical ideas other than the invention described in the scope of claims understood from the respective embodiments will be described.

(A) In the variable displacement pump according to claim 1,
The spool has a large-diameter land portion that slides with the valve body at both axial ends, and a small-diameter portion between the land portions, and the first control port or the second control is controlled by the small-diameter portion. A variable displacement pump characterized in that a port communicates with the drain port, and the land portion restricts communication between the second control port and the drain port.

(B) In the variable displacement pump according to claim 1,
The variable displacement pump according to claim 1, wherein the introduction port is provided on an end surface in the axial direction of the valve body.

(C) In the variable displacement pump according to claim 1,
Of the urging members constituting the urging mechanism, one urging member applies an urging force to the cam ring in a direction in which the eccentric amount increases, and the other urging member has the eccentric amount against the cam ring. A variable displacement pump characterized by applying an urging force in a direction in which the pressure decreases.

(D) In the variable displacement pump according to claim 1,
The variable displacement pump according to claim 1, wherein the first control oil chamber and the second control oil chamber are provided on an outer peripheral side of the cam ring.

(E) The variable displacement pump according to claim 1,
The variable displacement pump characterized in that the discharged hydraulic oil is used for lubricating an internal combustion engine.

(F) In the variable displacement pump described in (e) above,
The discharged hydraulic oil is also used in an oil jet that supplies hydraulic oil to a drive source of a variable valve operating device and a piston of an internal combustion engine.

10 ... Oil pump 11 ... Pump body (side wall)
12 ... Cover member (side wall)
15 ... Cam ring 16 ... Rotor 17 ... Vane 21a, 21c ... Suction port (suction part)
22a, 22c ... discharge port (discharge section)
31 ... 1st control oil chamber 32 ... 2nd control oil chamber 33 ... 1st spring (biasing member)
34 ... Second spring (biasing member)
40 ... Pilot valve (control mechanism)
41 ... Valve body 43 ... Spool 44 ... Valve spring (control spring)
51 ... 1st control port 52 ... 2nd control port 53 ... 1st drain port (drain port)
PR ... Pump room (hydraulic oil room)

Claims (3)

A rotor that is driven to rotate;
A plurality of vanes provided on the outer peripheral side of the rotor so as to freely appear and disappear;
By accommodating the rotor and the plurality of vanes on the inner peripheral side thereof, a plurality of hydraulic oil chambers are separated, and the eccentric amount of the inner peripheral center with respect to the rotation center of the rotor is moved so as to change. And a cam ring for changing the amount of increase / decrease in the volume of each hydraulic oil chamber during rotation of the rotor,
Disposed on the axially opposite sides of the cam ring, on at least one side thereof, is a suction part that opens to a hydraulic oil chamber that increases in volume when the cam ring is eccentric, and a discharge part that opens to a hydraulic oil chamber whose volume decreases in the same eccentric state. And a side wall provided with,
Each of the urging members is arranged with a set load applied thereto, and the cam ring is urged in a direction in which the eccentric amount increases based on the urging force generated by the two urging members. An urging mechanism configured to increase the urging force in a stepwise manner when the eccentric amount becomes a predetermined value or less;
The first control that guides hydraulic oil discharged from the discharge portion and applies an urging force to the cam ring in a direction in which the eccentric amount decreases against the urging force of the urging mechanism on the cam ring. An oil chamber,
The hydraulic oil discharged from the discharge portion is guided through a throttle, and a second force is applied to the cam ring in a direction in which the eccentric amount increases in cooperation with the biasing mechanism based on the internal pressure. A control oil chamber;
A second control communicating with the second control oil chamber, a first control port communicating with the first control oil chamber, a first control port communicating with the first control oil chamber by opening to one end side in the axial direction A valve body having a port and a drain port communicating with the low-pressure portion, and a spool that is slidably accommodated at one axial end side of the valve body and switches a communication state of each port according to the axial position thereof A control mechanism having a control spring that is housed and disposed on the other axial end side of the valve body and biases the spool toward the one axial end side with a biasing force smaller than that of the biasing mechanism,
In the initial position where the spool is urged by the control spring and moved to the maximum axial end of the valve body, the flow of the introduction port is restricted, and the first control port and the drain port communicate with each other. In addition, when the discharge pressure increases in the first state in which the flow of the second control port and the drain port is restricted, the introduction port and the first control port communicate with each other and the first control A variable displacement pump characterized by being configured to be in a second state in which the flow of the port and the drain port is restricted and the second control port and the drain port communicate with each other. A rotor that is driven to rotate;
A plurality of vanes provided on the outer peripheral side of the rotor so as to freely appear and disappear;
By accommodating the rotor and the plurality of vanes on the inner peripheral side thereof, a plurality of hydraulic oil chambers are separated, and the eccentric amount of the inner peripheral center with respect to the rotation center of the rotor is moved so as to change. And a cam ring for changing the amount of increase / decrease in the volume of each hydraulic oil chamber during rotation of the rotor,
Disposed on the axially opposite sides of the cam ring, on at least one side thereof, is a suction part that opens to a hydraulic oil chamber that increases in volume when the cam ring is eccentric, and a discharge part that opens to a hydraulic oil chamber whose volume decreases in the same eccentric state. And a side wall provided with,
Each of the urging members is arranged with a set load applied thereto, and the cam ring is urged in a direction in which the eccentric amount increases based on the urging force generated by the two urging members. An urging mechanism configured to increase the urging force in a stepwise manner when the eccentric amount becomes a predetermined value or less;
The first control that guides hydraulic oil discharged from the discharge portion and applies an urging force to the cam ring in a direction in which the eccentric amount decreases against the urging force of the urging mechanism on the cam ring. An oil chamber,
The hydraulic oil discharged from the discharge portion is guided through a throttle, and a second force is applied to the cam ring in a direction in which the eccentric amount increases in cooperation with the biasing mechanism based on the internal pressure. A control oil chamber;
It is configured to operate before the amount of eccentricity becomes minimum, and when the discharge pressure is equal to or lower than a predetermined pressure, the flow from the discharge portion to the first control oil chamber is restricted, and the first control oil chamber When the discharge pressure exceeds the predetermined pressure, the discharge portion and the first control oil chamber communicate with each other and the first control oil chamber A control mechanism that is in a second state in which the flow to the low-pressure part is restricted and the hydraulic oil in the second control oil chamber is discharged to the low-pressure part;
A variable displacement pump characterized by comprising: A pump structure that is configured so that the volumes of the plurality of hydraulic oil chambers change with rotation, and that discharges hydraulic oil guided from the suction unit by being driven to rotate from the discharge unit;
A variable mechanism that varies the volume change amount of each hydraulic fluid chamber that opens to the discharge unit by moving a movable member;
A volume change amount of the hydraulic oil chamber that is configured by two urging members arranged in a state where a set load is applied and opens to the discharge unit based on the urging force generated by the two urging members is provided. An urging mechanism configured to urge the movable member in an increasing direction and to increase the urging force stepwise when a volume change amount of the hydraulic oil chamber that opens to the discharge unit becomes a predetermined amount or less;
A first control oil chamber that guides hydraulic oil discharged from the discharge unit and applies a biasing force to the movable member in a direction against the biasing force of the biasing mechanism based on the internal pressure;
Hydraulic oil discharged from the discharge portion is guided through a throttle, and based on the internal pressure, a second control oil chamber that applies a biasing force to the movable member in the same direction as the biasing direction by the biasing mechanism;
Based on the discharge pressure, the variable mechanism is operated before the volume change amount of the hydraulic oil chamber is minimized, the hydraulic oil is guided to the first hydraulic oil chamber as the discharge pressure increases, and the discharge pressure is further reduced. A control mechanism for discharging the hydraulic oil in the second control oil chamber to the low pressure section when increased;
A variable displacement pump characterized by comprising:

Images